1. Field of the Invention
This invention relates to an improvement on a focus adjustment information forming device arranged to measure distances to objects appearing at a plurality of distance measuring points (or areas) set within a picture plane such as a photo-taking picture plane or the like specified by optical means which is used for an optical system such as a camera and to be focus adjusted.
2. Description of the Related Art
The devices of the above-stated kind has been known as wide-field distance measuring devices, which have been disclosed, for example, in Japanese Laid-Open Patent Application No. SHO 58-201015 and U.S. Pat. No. 4,470,681. After these disclosures, devices arranged to prevent a distance measurement error due to a foreground has been disclosed in Japanese Laid-Open Patent Applications No. SHO 59-193307 and No. SHO 60-172008. In addition to these known devices, a device arranged to exclude any object located nearer than a given distance as an obstacle has been proposed in U.S. patent application Ser. No. 184,931, etc.
However, these known wide-field distance measuring devices have been incapable of accurately discriminating a nearby object from a nearby obstacle such as the ground and thus have often failed to give accurate focus adjustment information.